rảnh hen

hỏi gì thì hỏi đi!

 (x + 1 + x - 1) + (x + 2 + x - 2) + ... + (x + 99 + x - 99) = 198

 2x + 2x + ... + 2x = 198

2x * 99 = 198

2x = 2

x = 1

 ( 2012 * 99 - 1006 * 198 ) * 2013

= ( 1006 x 2 x 99 - 1006 x 198 ) x 2013

= ( 1006 x 198 - 1006 x 198 ) x 2013

= 0 x 2013

=0

(2012*99-1006*198)*2013 = 0*2013 = 0

 ( 2012 * 99 - 1006 * 198 ) * 2013

= ( 1006 x 2 x 99 - 1006 x 198 ) x 2013

= ( 1006 x 198 - 1006 x 198 ) x 2013

= 0 x 2013

=0

mình bỏ vô cho có ý nghĩa

dấu * là j z bn

2014 x 99 - 1007 x 198

=199386 -199386

= 0

k mk  nha !

(2014 x 99 - 1007 x 198) = (2014 x 99) - (1007 x 198)

                                    = 199386 - 199386

                                     = 0

k mik nhé

1)tính

a)\(-18+\left(-19\right)+27\)

\(=-18-19+27\)

\(=-\left(18+19\right)+27\)

\(=-37+27\)

\(=-\left(37-27\right)\)

\(=-10\)

b)\(-198-194+286\)

\(=-\left(198+194\right)+286\)

\(=-392+286\)

\(=-\left(392-286\right)\)

\(=-6\)

c)\(-19-\left(-17\right)\)

\(=-19+17\)

\(=-\left(19-17\right)\)

\(=-2\)

d)\(-48+\left(-47\right)-\left(-15\right)\)

\(=-48-47+15\)

\(=-\left(48+47\right)+15\)

\(=-95+15\)

\(=-\left(95-15\right)\)

\(=-80\)

e)\(23-\left(-16\right)+\left(-80\right)\)

\(=23+16-80\)

\(=39-80\)

\(=-80+39\)

\(=-\left(80-39\right)\)

\(=-41\)

f)\(99-\left(-99\right)-198\)

\(=99+99-198\)

\(=198-198\)

\(=0\)

a. =-10

b. =-106

c. =-2

d. =-80

e. =-41

f. =0

=396 x 46 + 396 x 4

=396 x (46+4)

=396 x 50

=19800

198:0,5x46+99:0,25x4 

=18216+1584

=19800

198x(46:0,5)+99:(0,25x4)=198:23+99

                                    =18216+99

                                    =18315

mk chỉ đoán thôi nhé !

áp dụng hằng đẳng thức \(\left(A+B\right)^2\)=\(A^2\)+2AB+\(B^2\) ta có :

\(99^2\) + 198 +1 =(99+1)\(^2\)